The answer to the question
stated above is:
<span> Gas is easily compressible because the molecules of a gas are much further apart than
those of a solid.</span>
characteristic properties of gases: 
(1) they are easy to compress, 
(2) they expand to fill their containers, and 
(3) they occupy far more space than the liquids or solids
from which they form.
 
        
             
        
        
        
Answer:
(a) Pair 1: H₂S and HS⁻
     Pair 2: NH₃ and NH₄⁺
(b) Pair 1: HSO₄⁻ and SO₄⁻
     Pair 2: NH₃ and NH₄⁺
(c) Pair 1: HBr and Br⁻
     Pair 2: CH₃O⁻ and CH₃OH
(d)  Pair 1: HNO₃ and NO₃⁻
      Pair 2: H₃O⁺
Explanation:
When an acid loses its proton (H⁺), a conjugate base is produced. 
When a base accepts a proton (H⁺), it forms a conjugate acid. 
(a) H₂S is an acid. When it loses a proton, it forms the conjugate base HS⁻. 
     NH₃ is a base. When NH₃ gains a proton, it forms the conjugate acid NH₄⁺
(b) The acid HSO₄⁻ loses a H⁺ ion and forms the conjugate base SO₄²⁻.
      The base NH₃ accepts a H⁺ ion to form the conjugate acid NH₄⁺.
(c) HBr is an acid. When loses the H⁺ ion, it forms the conjugate base Br⁻.
    CH₃O⁻ accepts a H⁺ ion to form the conjugate acid CH₃OH. 
(d) HNO₃ loses a proton to form the conjugate base NO₃⁻.
     H₂O gains a proton to form the conjugate acid H₃O⁺.
 
        
             
        
        
        
To prevent the hydrolysis and to catalyse the reaction.
Explanation:
- Sulphuric acid is the catalyst and also a dehydrating agent in this reaction.
 
- Sulphuric acid is using in redox reaction because sulphuric acid is providing H+ ions which is necessary for this reaction to occur more quickly, but the sulphate ions from the sulphuric acid barely react during this process. So H2SO4 is adding in this reaction to make it more acidic.
 
-  H2SO4 is preventing hydrolysis by providing excess H+ ions into the reaction. H2SO4 is stable towards the direction of oxidation.
 
 
        
             
        
        
        
I would say all if no statements are available
        
             
        
        
        
The third option because the elements mentioned in that selection are in the same group, they must have similar properties.